From my hometown of Detroit, there's more grim news. The story that made today's headline comes from the State-authorized financial review team. They unanimously concluded that a fiscal emergency exists in Detroit. The city, with a population of about 700,000 residents, has $14 billion in long-term debt and a projected $100 million budget shortfall for this year. The story that didn't get a headline, but is equally important for the city's future, concerns the effects of lead poisoning on academic achievement among Detroit's school children. A newly published study in the American Journal of Public Health reports a strong association between high blood lead levels before age 6 years and "less than proficient" scores on the Michigan Educational Assessment Program (MEAP) tests given in grades 3, 5 and 8.
The City of Detroit's Department of Health and Wellness requires all children six years and younger who live in the city to receive an annual blood lead level (BLL) test. Laboratories are required to send all BLL results to the Michigan Department of Community Health. This data was linked with the Detroit Public Schools' database of MEAP test scores for students born between 1990 and 2008. The linkage resulted in 21,281 students with both previous BLL results and MEAP scores. The mean BLL for the 21,281 youngsters was 7.12 ug/dL taken at the mean age of 3.1 years.
The analysis revealed a strong, statistically significant dose-response relationship between BLL and scores on the three MEAP test (i.e., math, science and reading.) The higher the mean BLL the worse the MEAP score. The authors note that their analytical models could successfully predict the probability of scoring either "partially proficient" or "not proficient" on all three MEAP tests. (They grouped these two categories and labeled it "less than proficient," and grouped the other two categories (i.e., advanced and proficient) as "proficient or better.") When the researchers adjusted for other factors that may be associated with academic achievement, such as maternal education and socio-economic status, the dose-response relationship remained strong. The table below shows, for example, students who had BLL greater than 10 ug/dL at age six or younger were 2.4 times more likely to score "less than proficient" when they took the MEAP math tests in grades 3, 5 or 8.
Similar negative associations were reported at each exposure category for the science and reading test scores. These findings are consistent with other studies showing a relationship between early childhood lead exposure and subsequent and permanent intellectual deficits (e.g., here, here, here, here.)
This analysis of data from more than 21,000 students in the Detroit Public Schools is notable for other reasons. There is no safe level of lead in a child's body, yet the vast majority of these Detroit youngsters had BLL that exceeded 5 ug/dL. In fact, there were 67 children in the study population who had BLL that exceeded 50 ug/dL. There are less than 100,000 students enrolled in the Detroit Public Schools. This data suggests that a significant percentage of them were (or still are) lead poisoned and it has adversely affected their academic achievement.
The City of Detroit's long-term recovery not only depends a solid financial footing, but also on a healthy environment for children. The ill effects of lead poisoning on children's cognitive development have been known for decades. So have the primary prevention methods to protect children from being exposed to lead, especially in their homes. This study should be a wake-up call to the City of Detroit's leaders to invest in their Lead Poisoning Prevention and Control Program, including new sanctions to hold landlords responsible for addressing lead-paint hazards in households where children live or visit.
Its not just academic performance. Lead exposure leads to poor impulse control and violent behavior as well. Recently Mother Jones published an article about the lead/violence conection. Detroit, nor any other city can not survive with led poisoning.